[css-fonts-5] or [css-text-4] Text Fitting: Which spec to put the feature into?

[kizu]

In the original issue it was resolved to be placed in Fonts 5, however Chrome team’s feedback argues:

• We think the feature belongs to css-text, rather than css-fonts.
  It's similar to the text-align property.

We should resolve on if we want it to stay in Fonts 5, or move to Text 4.

I don't have an opinion on this. I'll open the remaining issues with the [css-fonts-5] in their titles and labels as it was resolved so far, but we could adjust things as we go.